The present invention relates generally to agricultural bale handling and hauling machines, and more particularly to such a single sensor control system for a bale wagon that automates the loading of large bales onto a bale wagon.
The Mil-Stak® big bale loading attachment was developed as a way incorporate big bale handling capability on self-propelled or pull-behind bale wagons. The Mil-Stak® big bale loading attachment comprises a bale clamping apparatus connected to a pivoting lifting arm. The lifting arm is coupled at one end to the bale wagon for pivotal motion about a single axis, the axis being angled relative to the bale wagon. Loader arm movement is accomplished using a single actuator acting on a lever arm to pivot the lifting arm through approximately 180 degrees of motion. A full sweep of the loader arm requires the actuator to be moved in a first direction for approximately half of the rotation and then in an opposite direction for the remain half of the rotation. A second actuator actuates the clamping apparatus.
An automated system for controlling movement of the lifting arm and clamping apparatus is disclosed in U.S. Pat. No. 8,112,202 issued to Fackler, et al. to replace the previously used manual control method. The automated system relies upon multiple sensors to manage movement of the lifting arm as it rotates through an apogee in its movement at which point the direction of movement of the single actuator is reversed to complete the lifting arm rotation. The known configuration requires a mount to facilitate placement of two sensors about the rotational axis angled approximately 120 degrees apart and a large cam surface to serve as a target for the two sensors. The result is a sensing system requiring substantial space in the area surrounding the lifting arm pivoting connection, an area that leaves the sensing apparatus relatively exposed to debris and damage.
Significant advantages would be realized by a control system for a bale lifting arm that could be more compactly retrofitted onto the Mil-Stak® big bale loading attachment to reduce the necessary installation space and attendant risk of damage. Additional advantages would be realized by a control system for a bale lifting arm using fewer position sensors while offering comparable control performance. A system in which the bale lifting arm position could be monitored by a single position sensor through its 180 degree range of motion would offer the greatest benefit to reducing cost, part count, and system complexity while also enabling the system to be more compactly packaged on the lifting arm.